1. Technical Field
The present invention relates to a method for producing electrophoretic particles, an electrophoretic dispersion liquid, a microcapsule, an electrophoretic device, and electric apparatus.
2. Related Art
In general, when an electric field is applied to a dispersion system prepared by dispersing fine particles in a liquid, the fine particles are moved, i.e., migrated, in the liquid by the Coulomb force. This phenomenon is known as electrophoresis. Recently, electrophoretic devices that display desired information (images) using this electrophoresis have attracted a great deal of interest as a novel display device. JP-A-2002-202534 is an example of the related art. The electrophoretic devices advantageously have a display memory property in a state where the application of voltage is stopped, and a wide viewing angle property. In addition, a display with high contrast can be achieved with low power consumption.
Furthermore, since the electrophoretic devices are nonluminous display devices, these devices are eye-friendly, compared with luminous display devices such as a display including a cathode ray tube. JP-A-2002-202534 discloses an electrophoretic device in which microcapsules containing an insulating colored liquid and charged particles therein are sandwiched between a pair of transparent electrodes. In this electrophoretic device, when a voltage is applied between the pair of transparent electrodes, the charged particles migrate in the colored liquid toward one of the electrodes according to the direction of an electric field generated between the electrodes. Consequently, an observer can see the color of the charged particles and/or the color of the colored liquid. Accordingly, desired information can be displayed by patterning at least one of the electrodes and controlling the voltage applied thereto.
In a known electrophoretic device, charged particles having a desired charge state are generally selected for use. Alternatively, particles are charged by adhering a coupling agent, a polymer, or the like on the surfaces of thereof. However, the types of the coupling agent and the polymer that can be used are limited. Therefore, in any case, it is difficult to control the charge state of the charged particles to be a desired state. This is because the charge state of particles is difficult to control. It has been desired to develop a method for easily controlling the charge state of particles to a desired state.